The present invention relates to a device for operating a windshield wiper with an automatic wiper control, comprising an input stage that detects the activation of the wiper control, a sensor unit that detects the degree of wetting of a windshield, an evaluation unit that amplifies and evaluates a sensor signal, as well as an actuation unit for a wiper motor.
A device of this type is shown in DE 41 12 847 A1, which has an automatic wiper control with a sensor unit and an evaluation unit for amplifying and evaluating the sensor signal, which unit transmits a control signal to an actuation unit that actuates a wiper motor. The amplification of the sensor signal is adjusted by means of an automatic control to a quiescent level, and a wiping operation is triggered if, starting with this quiescent level, a wetting event on the windshield is detected via the sensor unit, which results in falling short of a predetermined threshold.
The adjusted quiescent level here takes into account the manufacturing tolerances of individual components of the sensor unit, as well as tolerances for mounting the sensor unit. If the automatic wiper control is not turned on, it is not always certain that, when the control is turned on, the device will function at optimum sensitivity, so that it is possible that the wiper will not react optimally when the windshield is first wetted.
It is, therefore, the object of the present invention to provide a device for operating a windshield wiper of the aforementioned type, makes sure that when the wiper is turned on, it will respond optimally to activate the automatic wiper control as a result of a wetting event.